How to discharge old batteries?

I know it seems an odd question, but it is a SERIOUS one.

The discharging of Apple batteries [mainly I am interested - iPhone and iPads] is VERY important.

You do not want to have a pile of old batteries still charged.

You are increasing chance or FIRE!

Also, they might be defective when replacing them too and would be MUCH better discharge them properly and securely, then dismount it.

So, any ‘professional’ here can recommend the correct tool to do that?

iPhones/iPads have different connectors too.

So, tools must have that too.

Thank you

M